In Direct-TV data protocol, program guides are sent as a collection of data packets. FIG. 1A shows a DSS transmitter 101 that transmits DSS data packets that are received by a DSS receiver 102 and routed to a SDRAM 103. The packets are stored in a random order.
FIG. 1B shows a typical SDRAM 103 with data packets (PO–P8) 105 stored at different locations 104, illustrated as LO–L8. FIG. 1B shows a first set of data packets 106 (packets PO–P4) stored at memory locations L4 to L8 respectively and a second set of data packets (P5–P8) 107 stored at memory locations LO to L3 respectively. However for efficient processing, the packets should be stored in the order illustrated in FIG. 1C. i.e. packet PO should be stored in location LO, PI in location L1 and so forth.
Currently a second memory buffer is used to reorder the data packets as they are received. FIG. 1D shows a second memory buffer 111 used for reordering data packets. When the first set 106 is received, in step S101, packets PO–P4 are moved to memory buffer 111. In step S102, data packets in second set 107 (P5–P8) are moved to the desired locations, L5–L8, as shown in FIG. 1C. Finally, in step S103, data packets in set 106 are moved to locations L0–L4. Currently, the reordering system is expensive and hence increases the overall system cost.
Therefore, what is needed is a system that can efficiently reorder incoming data packets without expensive memory buffer requirements.